Abstract: According to the requirement of stability analysis for karst cavity and in-situ stress analysis,conditions of drilling-dissolving mining for deep rock salt mine,and practical experience of research on in-situ stress measurement in deep rock salt mine,the selection principle of measurement methods,measured points and samples are determined. The method of building up the coordinate direction of non-directional drilling cores in sediment strata is proposed. Based on the principle of in-situ stress measurement by the Kaiser effect of acoustic emission,the multidirectional sampling and the ellipsoid regression analysis of in-situ stresses are made. Multivariable nonlinear fitting is made to determine a general form of in-situ stress ellipsoid,and then a quadratic orthogonal transformation is made to determine the standard equation of in-situ stress ellipsoid,so that the magnitude and direction of three principal stresses can be obtained. The presented method can avoid more effect of testing errors and get reliable measurement results. According to the testing and analysis results from Changshan Salt Mine,there is horizontal tectonic stress in deep strata,and the direction of major principal stress turns to vertical direction from horizontal direction at the depth of 800 m,and at the depth of 1 000 m the major principal stress is about 30 MPa.